Next generation network (NGN) denotes the fully converged network of the future that provides advanced services of many kinds with many modalities (voice, video, data, signaling/control, management, connectivity, etc.). At the connectivity level, NGN may resemble the Internet with one difference: It may be like the Internet in its ubiquity, in the use of different continuously evolving access and backbone technologies, and in its universal use of the Internet Protocol (currently IPv4 evolving to IPv6) at the network layer. NGN connectivity, however, may be fundamentally different from the current Internet in that it may be quality-of-service (QoS) enabled, and may ultimately support QoS on demand. Quality of service is used in its broadest sense to include bandwidth, delay, delay variation (jitter) and other relevant metrics. Connectivity in NGN may be realized through multiple interconnected infrastructures, both access and backbone, operated within distinct administrative domains by different facility-based network service providers (NSPs).
Using the connectivity infrastructure of NGN may be an ever expanding set of sophisticated “applications.” Rudimentary forms of some of these applications are currently provided by the Internet. These early services range from communication applications (e.g., email, IM, VoIP) to entertainment services that involve content delivery (e.g., music on demand, low quality video on demand, gaming) to a vast array of data and information services (e.g., browsing, searching, E-commerce, information retrieval, software distribution). Because the current Internet is not QoS-enabled, these services are typically provided on a best-effort basis, often with inconsistent or unpredictable quality and end-user experience. Furthermore, most applications today are “atomic” in nature, each offered independently on its own, typically with its own interface and other ancillary features like authentication and/or authorization. NGN may begin to change this paradigm first by enabling the applications to use the on-demand QoS capabilities of the underlying connectivity network to provide a much richer and more consistent user experience. More significantly, however, applications may progressively lose their atomic nature and may become increasingly more intertwined and composite, and hence more useful to the end user. Thus one may be able to invoke feature-rich multi-modal communication capabilities with information sharing, multimedia conferencing with elaborate collaboration features, multi-player gaming with advanced real-time communication enhancements, E-commerce combined with information and communication features that relate to product marketing and support, and education and training services that will virtually erase distance barriers by providing near-presence experience. NGN applications may also incorporate more unified and holistic interface and support capabilities like single sign-on, management of user profile, presence, availability, and seamless mobility in ways that may not have been possible in the past.
The current paradigm of IP application development basically treats the Internet (and subtending intranets) as a ubiquitous connectivity infrastructure and designs and implements each application at its edge in an autonomous manner, complete with all the supporting capabilities that the application needs. In this paradigm, the degree of convergence has advanced to encompass ubiquitous IP connectivity, in contrast to the older paradigm in which different types of applications would use their own connectivity infrastructure (voice telephony on wired and wireless circuit switched networks, video on DBS and HFC infrastructures, email/IM and information services on the Internet, signaling and control on SS7, etc.). A large set of today's applications are developed and offered by entities that do not own a connectivity infrastructure (e.g., Microsoft, AOL) and just use the public Internet as a common best-effort connectionless delivery mechanism. This architecture is depicted, for example, in FIG. 1 where the application layer is decomposed into a collection of more or less independent application stacks. The collection of shapes in each application stack represents a set of supporting capabilities needed by the application for its proper functioning. As graphically depicted in FIG. 1, many of these supporting capabilities are common across different applications.
Just as the IP connectivity network may undergo fundamental changes to support QoS on demand, so may the application layer architecture to enable rapid, cost effective rollout of sophisticated next generation application services.